> Anyway, what if I want to make hi-res hdr panos? I haven't found any
> software that works on Linux (other than enfuse/enblend) that can handle
> very large pictures without eating all available memory :-(

I run into that problem with most software, including my own stuff to
an extent.

I have been reading papers on exposure blending over the last couple
of days, and think that the enfuse algorithm might have certain
advantages with an hdr input.

As I understand it enfuse does something like:
- for each image:
  - for each pixel generate a weight using some metric based on
saturation, contrast and exposure.
  - perform multiresolution blending.

I haven't looked at the enfuse source, but the original paper suggests
doing this once per channel (xyz or rgb?).

I'm working in an xyY colour space, and want to preserve my colours so
I only modify Y, so it becomes:

- extract luminance channel.
- generate set of global tone map parameters (images)
- for each of these images:
  - generate weight using slightly simpler contrast + exposure
metric.  I get a "fast out" for over & underexposed pixels, as I can
just read off the tone mapper parameters.
  - perform multiresolution blending.

If I'm willing to accept a loss in precision and, say, work in 8 or 16
bits rather than floating point then I should be able to significantly
cut down my working memory requirements.  Local tone map algorithms
are mostly cheap enough that I can generate pixels on demand.  I'm
limiting the dynamic range of each exposure, so I have the luxury of
choosing a simple function anyway.

A project for next month.

In the meantime I have been working on a module to do silly special
effects like this '-)

http://www.spectral3d.co.uk/misc/lined2.png
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